ECMAScript parser 
An ANTLR4 grammar for ECMAScript based on the Standard ECMA-262 5.1 Edition from June 2011.
Install
To install this library, do the following:
git clone https://github.com/bkiers/ecmascript-parser
cd ecmascript-parser
mvn clean installExample
Let's say you would like to extract all regex literals from the following script:
// comment /./m
var x = a / b / m; // division, no regex!
/.*?\/\n\\(?!$)/.match('some text')
/*
another
/no pattern!/
comment
*/
var z = /a/mIf you look at the parser rule for a JS literal:
literal
: ( NullLiteral
| BooleanLiteral
| StringLiteral
| RegularExpressionLiteral
)
| numericLiteral
;you see that it can potentially match a RegularExpressionLiteral.
We can now retrieve all regex literals by attaching a tree listener to
the parser and upon entering the literal rule, we simply check if
RegularExpressionLiteral() is not null, in which case we print the
contents of this token:
String script = "// comment /./m \n" +
" \n" +
"var x = a / b / m; // division, no regex! \n" +
" \n" +
"/.*?\\/\\n\\\\(?!$)/.match('some text') \n" +
" \n" +
"/* \n" +
"another \n" +
"/no pattern!/ \n" +
"comment \n" +
"*/ \n" +
" \n" +
"var z = /a/m \n";
// Create the parser.
ECMAScriptParser parser = new Builder.Parser(script).build();
// Walk the parse tree and listen when the `literal` is being entered.
ParseTreeWalker.DEFAULT.walk(new ECMAScriptBaseListener(){
@Override
public void enterLiteral(@NotNull ECMAScriptParser.LiteralContext ctx) {
if (ctx.RegularExpressionLiteral() != null) {
System.out.println("regex: " + ctx.RegularExpressionLiteral().getText());
}
}
}, parser.program());Running the code above will print the following:
regex: /.*?\/\n\\(?!$)/
regex: /a/m